1. Field of the Invention
The present invention is related to an electro-photographic type image forming apparatus and a process cartridge used in this image forming apparatus.
2. Description of the Related Art
As a conventional image forming apparatus, such an image forming apparatus is well known in this technical field in which a process cartridge is detachably mounted on a main body of the image forming apparatus. As one of conventional process cartridges, such a process cartridge is known in which both a cleaning apparatus and a developing apparatus are relatively arranged in an upper/lower positional relationship, while sandwiching therebetween an optical scanning path.
In the image forming apparatus employing such a process cartridge, in such a mode that transferring/fixing operations are carried out while recording mediums are transported along a substantially vertical direction, the developing apparatus is arranged under the optical scanning path. As a result, in order to reduce the height of this image forming apparatus, since the developing apparatus is located on the lower side of the optical scanning path, the height of the developing apparatus is required to be decreased. Since the developing apparatus contains a developer storage unit for storing thereinto developer, the size of this developer storage unit must be reduced. However, while the developer storage capacity is maintained, it is practically difficult to make the developing apparatus compact.
An object of the present invention is to provide a process cartridge and an image forming apparatus using the process cartridge, which can be made compact, while a sufficiently large developer storage capacity is maintained.
To achieve the above-described object, a first feature of the present invention is realized by a process cartridge detachably mounted on a main body of an image forming apparatus, comprising: an image carrier; and a developing apparatus having a developer storage space, for developing a latent image formed on the image carrier to produce a visible image; in which the developer storage space is segmented into a first developer storage portion and a second developer storage portion along upper/lower directions, while sandwiching therebetween a latent image writing position of the image carrier into which the latent image is written; and also the first developer storage portion is communicated to the second developer storage portion via a developer path. Since the developer storage space is segmented into upper/lower portions while sandwiching therebetween the developer path, even when the developer storage capacity of the second developer storage portion located under the latent image writing position is reduced, the necessary amount of the developer can be replenished with the developer stored in the second developer storage portion.
In the case that, for instance, a scanning type laser exposing apparatus is employed as a means for forming a latent image, in order to secure an optical scanning path outputted from this scanning type laser exposing apparatus, a window portion which constitutes the optical scanning path is formed between the first developer storage portion and the second developer storage portion, and also, both the first developer storage portion and the second developer storage portion are separated from each other along the upper/lower direction while sandwiching therebetween this window portion. Also, developer paths may be preferably provided on the both sides of this window portion.
Preferably, the first developer storage portion is provided with a first stirring/transporting member which stirs/transports the developer from a center of the first stirring/transporting member to both sides thereof. This first stirring/transporting member may be constituted by, for example, a wire line material. Although the first stirring/transporting member may be formed in a crank shape, this first stirring/transporting member may be formed in a helical shape in such a manner that the wire line materials are wound from a center portion thereof (viewed from axial line direction) toward both edge portions thereof along different winding direction.
Preferably, the second developer storage portion is provided with a second stirring/transporting member which stirs/transports the developer from both side portions of the second stirring/transporting member to a center portion thereof. As a result, the amounts of the developer can be made equal to each other along the axial direction. It should be understood that when the developer owns good fluidity, this second stirring/transporting member need not employ a specific structure, but may be formed in, for instance, a crank shape.
Also, the present invention may cover an image forming apparatus having the process cartridge with employment of the above-explained construction.